What's the greatest bargain in SET these days?

I think buy the one you like best.

How about the Baby Sophia? I like that its made in Virgina, not far from me.

Reb, nice blog. You are the Lewis and Clark of set amp builders from where I stand. :-) If only they had a web blog back in their day.

I was impressed with sound of glow audio amps I heard at a show a couple years back.

92 db is borderline for a set but might play fine to moderate volume with a lot of music.

Good stuff!!!

That Coincident definitely looks like a winner.

JMCgrogan,

I've never had a device with variable feedback.

You indicated the changes affecting bass and detail.

Could the detail be associated with more relative brightness?

I notice with certain good quality headphones that tend towards less of a low end that things sound a lot different in the midrange. I hear things I might not have focused on otherwise, but I am hard pressed to say that they are not there otherwise. ITs more like a different perspective on the music where different things become more prominent, more of a difference in what is emphasized I think, but the result of more emphasis in the midrange might often be perceived as more detail since that is where most music happens.

Then there is the whole bad harmonics rap on NF. I understand this in theory but have difficulty pinpointing it in practice. IT just does not seem to be a big issue to me if the gear is designed well.

I'd like to have adjustable NF in order to experiment more but don't, so I guess I am just looking for the impressions of others in this regard.

Thanks.

I'm very tempted to try that amp with my Triangle Titus XS monitors. IF my wife would have it in her sunroom that is. It's a modern Victorian style house and she loves retro, so maybe.

Charles,

Yup, I'm with you 100% on all your points.

That one should be so good you don't even know its there to a bargain at that price.

No doubt it must be good and built well, but so would the $1200 Coincident amp it seems.

I've heard much more expensive Audio note SET amps on large very high efficiency horns. The sound was outstanding. But I find I can do as well in most rooms for a lot less. i can also understand how some might only be satisfied with teh biggest and best available at any price, but unfortunately my budget is not likely to enable that in my case.

" However, one could make a case that a great value is that piece of equipment that delivers the level of performance one seeks, regardless of relative price."

No doubt that's pretty much it.

I think there are differences in how to go about it though. You can start small and then improve by increments until you hit your target. That's how I tend to work.

Or you can start with a big investment with the cost perceived as the insurance policy and go from there as needed. But in this case you will never know what might have been achievable for less. Ones bank account balance ( or perhaps even credit rating though personally I would not borrow money for any luxury item like this) is likely a good determining factor for where one will start.

But to truly find the best value, you have to stat small and make moves only when needed to hit your target.

Of course you also have to know what the target is. To do that, I listen to as much live music as possible and also the best "reference" systems that I am able to. Then at least I know what is or is not possible as well as what sound I like best.

What is it exactly that changing the rectifier tube improves?

Thanks.

Thanks for that but I am wondering what the specific noticeable effect to the sound is for this amp specifically by changing the rectifier tube as suggested.

Mik,

That helps thanks.

Can you describe the specific timbre differences you hear with stock versus alternate rectifier tube?

Thanks.

Czar,

Not a bad idea. I've seen some SET amp kits advertised. Haven't tried anything like that since building electronic kits as a kid, but if I could do it back then I probably could now.

Did you have any particular kit/design in mind?

Mik, good answer!

I would have high hopes for the stock tube by design but rolling is always a nice option to have. Often it just comes down to personal preferences with tube rolling I have found to-date.

I see This One comes in at just over $200 for parts. I'd be interested to know if anyone has built it and compared.

Rebbi, I'd be willing to bet the stock tube issue just build down to individual preferences and synergies with their stuff in their specific cases. When different tubes sound different, the maker has to decide which to provide. They can't provide them all.

The one input issue is a factor but there are workarounds for that, using an eternal switching device for example.

The volume knob location may or may not be a real issue. Existing owners could probably say best.

Its a fine looking product, but no single product can meet everyones needs best. Features, aesthetics, etc. matter too in addition to sound quality, and are often the deciding factor.

The set amp I have actually heard in recent years (at Capital Audiofest) that I mentioned early on here and liked a lot was the GLow Audio Amp 1. I also like the price and compact size. Build quality there would seem top notch as well, direct wiring, hand wrapped xformers, etc., according to their site.

They have a newer larger push/pull 15 watt model as well. On their site, they are advertising free dac and pair of either Def Audio, Triangle, or Klipsch speakers with purchase that amp. Or dfree dac but no speakers for the smaller Amp 1.

Its gotta be. It goes against physics for a small box to be more efficient and have flat extended bass. Just cannot be. But might sound quite good still at low to moderate volume and soft clip increasingly as the volume goes up, limiting dynamics. Large scale dynamic works would suffer most. End results at higher volume might still be quite good, but can't be optimal in terms of dynamic headroom.

Smaller high efficiency speakers with low ends that roll off at higher frequencies, 50-60 hz or above say, like my "90db" Triangle Titus XL speakers for example would be less affected and probably a better match overall. Or larger more full range high efficiency designs.

I like having a sub output as an option for a set. That would help open up more possibilities for a SET amp.

One thing I would consider were it me with any tube amp is how hard the tubes are driven which factors into how often they will likely need to be replaced. This can vary quite a bit from amp to amp from what I read.

The 5-7 watt SET amps that I have heard do surprising well with even moderately efficient speakers in many cases with many kinds of music. They have their unique charms within their limitations. It takes very large very efficient speakers to get around the limitations completely based on what I have heard which to date supports my general understanding of the physics involved in driving speakers optimally.

I have only heard one SOTA such full range system where dynamic headroom seemed unconstrained, a very large multi unit custom GOTO horn system, similar to Avantgarde with separate bass modules in appearance/design, run off a pricey Audio Note SET amp. I'm sure there are others but the key is to havbe very large very good, very high efficiency speakers designed specifically with SET type amps in mind.

But on a smaller scale, I have heard various very nice sounding SET based systems with smaller speakers, but each of course has its technical limitations that may or may not matter depending. THis stuff is as much about personal preferences as anything, though for me. With SET amps and many smaller speakers, they still can as long as higher volumes, low end extension and optimal dynamics are not key ingredients in the preferred recipe.

No doubt that things need not be perfect from a technical perspective in order for good music to be made. Happens all the time. Most everything has some limitations. The key is to understand what they are and how they may or may not be relevant case by case.

The Coincident is a very nice product. SO is the Glow. Newer Glows advertise two inputs compared to one in older models which might be of value in this case plus they come in still for several hundred dollars less, not a trivial amount if product is suitable. I do not recall what speakers I heard it with but they were smaller monitor types and sound was top notch. I've heard other similar wattage amps drive Nola BOxer monitors similarly well also. I've also heard similar amp drive Zu Essence, which are larger and more efficient and still thought the amp was underpowered for rock music even based on what I heard. Jazz and acoustic music in general sounded great. The Zu guy there even admitted the SET was probably not optimal for all kinds of music. I had to ask for him to play some Rush as a test. I think the vendors like to play to audiophile desires for more exotic gear, like SETs, sometimes, knowing that like most things there will be limitations.

The GLOW also has the cool glowing color ring around the volume that changes color. :^)

My app would be as a headphone amp for both STAX and conventional phones and to perhaps try with my Triangle Titus XS speakers in my wife's sunroom, where small and inconspicuous works best.

Currently the Triangles run off my main system downstairs via in-wall speaker wiring. I have a dedicated setup for the Stax in my family room running off a 70s vintage Yamaha receiver fed by Squeezebox Touch that works quite well, but I would love to hear it with a really good sounding tube amp.

Reb, I see a $3000 list price on the antique web site yet saw another listing on the web for just over $1000, so based on that limited exposure, I'm wondering how much that unit is really worth? Agon blue book might be an indicator.

Rebbi,

What speakers was that guy using? Decapos as well?

Also I wonder what the song was? If a chamber work, probably not a big challenge. If a symphony, Rush, Metallica, or a well recorded big band, I wonder if outcome would be the same?

Agree with TG.

I have only heard SETs perform to the max with very high efficiency horns to-date, over 100db efficient, similar to Avantgarde Trio.

I heard one set fall short with Zu Essence speakers once at a show. Not with the music demoed (small scale jazz and classical works) but with music I requested as a test (Rush). This was in a typical hotel-sized guest room, not large. The lack of dynamics was noticeable even at moderate volume to me.

DeCapos are less efficient than Zu I think.

So any of these may well work in many cases, but seems to me the beefier designs will have the one-up.

Rebbi, BTW, after the Zu/SET demo with some challenging rock music, the ZU guy doing the demo admitted the amp was underpowered for the task most likely. I wish I could remember what amp exactly was used, but do not. I don't think it was any of the main contenders here.

It registered to me that Zu seemed more interested in marketing how well their speakers can do with a flea powered amp than they were with showing them off at their best.

On the other hand, I heard a Jolida FX10 do very well running a small pair of Nola monitors another time, with sound that hit way above what I expected. However, those were small monitors with limited low end extension and I think that was the difference. Your DeCapos are much bigger hitters in terms of low frequency extension I believe and I think that is where the challenge will come in some cases, if its something that might matter for you.

The compromise I hear in lesser cases is more about dynamics than volume, though certainly volume can be an issue as well.

"your head seems to be spinning in the typical audiophile conundrum"

YEs, that is the curse that goes along with all this. What's best? What will work best? What is best value? What to do?

So many choices. The good news is they are all mostly good ones. What's best depends on goals (and often budget).

If money is no issue, its not a problem.

If it is, then best thing to do is start with trying a less expensive option that seems likely to meet the goals. Buy used from a trusted seller so as to have confidence and not overpay. Then if things do not work out, sell and repeat process until you hit the bulls eye.

Nothing new here, just reiterating. Its really the best way to go. The main prerequisites are patience and some extra time spent tweaking gear along teh way.

Rebbi, not to late to just go back to some good SS amplification before taking a deeper dive into tube amp land. :^)

I bet TAD hibachis would sound really good with those Decapos for well under $1000 and no tubes worth mentioning. They even each have a volume control so all that you would need is your current gear and something like that inexpensive Decware switch box, or may be a decent passive pre-amp at worst.

Just saying....

Charles,

Yes, I mention those purely for the potential sound and performance with Ref3a DeCapos specifically for very modest cost, not the underlying technology used.

I have a pair I have used with all my speakers, Dynaudio, Triangle, OHM. Results are top notch in every way and most lovely with them all. Their only limitation I have found is with my larger OHMs in my larger room where they can run out of gas somewhat before reaching concert levels in comparison to the BEl CAnto ref1000m monoblocks I normally use with those, which never even break a sweat much less run out of gas.

Good performance from a technical perspective and good sound are two different but related things.

Just keep in mind that any speaker will work with most any amp. Its just a matter of how well and how it sounds.

Rebbi's done his homework and pretty much knows the SWOT analysis at this point I would say.

I think there is a decent chance any of the prime candidates could work out for Reb given his goals. Is it a technical match made in heaven? I'd say no, but the end results might still hit the bulls eye, at least in this case.

Building the kit sounds like a fun project in particular.

"What troubles me is that rebbi needs to make a decision without benefit of an audition."

That's the problem.

He could always buy used initially to get a feel, then sell and buy new if needed/desired. That would be the risk mitigation strategy I would recommend from a financial perspective.

...or buy new with vendor provided support including a return policy for reasonable cost to the buyer.

Kit would be fun, but I would not know what to expect the resale value to be if it did not work out for some reason.

Tube gear in particular can be risky IMHO. I'd probably go with the product I like from a vendor with good support and reasonable return policy, if it were me.

I would buy that explanation. In my case I have a set on the radar screen somday as a good solution with a wider variety of speaker designs for lower level more casual listening. Good for the ears no doubt. That would be another advantage for music lovers looking to preserve their hearing. Also I believe lower listening levels tend to fare better more often for minimizing listening fatigue which tends to increase listening enjoyment. At least for forms of music conducive for low level listening.

More so then tonal imbalances that would be associated with a "difficult load". if there is a problem, I think it will be related more to a flea powered SET "running out of gas" sooner due to the DeCapo combo of low end extension and moderate efficiency and resulting in (soft) clipping that has to impact dynamics. It exponentially takes more power to produce lower frequencies with smaller speakers/drivers, , so even modest bass extension can have significant impact.

Dark,

Good to hear from you. IT's been awhile.

I do not think any good speaker designed for high power amps can perform equally well with low power. It might transform in a still musically desirable way in some case, but there will be an inevitable loss of "accuracy".

But no speaker vendor will willingly tell you this. They will say their speakers work well with most anything within certain parameters at best because, well, they need to sell speakers and its a pot shot to predict whether a customer will be happy or not before the fact.

The low end roll off comment is interesting. If you can live with some low end roll off, those precious few watts can go further. Could be a good thing for dynamics otherwise. An amp spec worth considering with more borderline efficient speaks like the decapo. Remember that loudness and dynamics are two different things. It's the dynamics mostly that have been lacking In demos I have heard using underpowered sets with speakers of considerably higher efficiency even at moderate volume in not large rooms.

Charles,

It's probably just amp/speaker synergy. Case by case. Each case may be a bit different . The best set demos I have heard have been excellent but with very large very efficient speakers designed for the task. Results of the best ss based combos are in the same league. No two exactly the same though. Source material makes a huge difference as well of course.

Good choice. Sounds like a fun project ahead!

I built many a kit as a kid. Its the best way to truly understand how things work and a little education always goes a long way.

Audiogon will be +1 SET guru when Rebbi is done.

I read that SET amps are more prone to limits in frequency response (ie not necessarily reasonably flat from 20-20K) than most other amp architectures. Low end extension is without doubt where most power is required. Its basic physics. Limited low end extension might help account for better performance at higher listening volumes in some cases. Transformer and power supply build quality matter as well no doubt, but a watt is still a watt and can only go so far.

The Coincident SET sis advertise 20-20K frequency response in their specs as I recall. I would think that kind of low end extension would up teh ante in terms of needed speaker efficiency and overall size needed to deliver flat response down to the usual 20 hz or so from a SET amp.

That's just what I get out of it. Maybe some others more experienced can help clarify.

DECware website also shows a FR graph for their set indicating extended flat response using a "real speaker load" (paraphrasing) but I did not see where the exact speaker load used to produce the graph was indicated. I suspect it was very large and very efficient. Anyone know?

REbbi,

Reading your historical info on teh blog, it may have been covered back then, don't recall but your Class D amp had only 10000K input impedance which is minimal and far from optimal for use with a tube pre-amp. FWWW, I'd be willing to bet if you were using it with teh Manley or most any tube pre-amp results might not be that great. COuld have impacted the OHMs easily if in the picture then, as might a lively room.

Assuming a good fit into the room, perhaps some low end extension, but I would not expect much of a difference if integrated well into the right size room. If so, a sub or two could close the gap.

The OHM Walshes of a particular vintage (currently Micros and X000 series) are all designed to sound inherently the same in their target size rooms. Bigger drivers can deliver more output at lower frequencies obviously, but that's about it. The rest is the same just scaled up or down, which is quite a unique thing. You can get the best sound possible in a small room with micros or 100s, larger models add little or nothing.

My Walsh F5s and 100 series 3 speakers are both one series old. 5X models (the largest) come with 4 3 way adjustments on each speaker that provide flexibility in fitting those into any room, large or small. I have compared them to my 100s in my smaller room suitable for either and the sound is in fact essentially the same. The 5s are much bigger and are overkill though for a small room alone. They sit normally in my large L shaped room which is 20'X30' more or less. My smaller room(s) are both 12X12, each with very distinct acoustics.

Schubert, teh other sonic distinction would be between newer more rectangular cabinets with built in plinth below and older cabinets with sloped sides and no plinth. The vertical Walsh style driver and bottom port result in a lot of bass energy in particular being imparted vertically to the floor compared to other designs, so something to be aware of and manage.

Reb,

I would withhold final judgement on Class D until you hear a well matched setup. Stop by my house someday.

MD, I'll contact you via agon email about your OHM question.

Reb. How many more steps?

Definitely reminds me of my electronic kit building days as a kid except this one costs way more and will sound much better than anything I've ever done. Still have all the tools though so with those and your journal one would be armed and dangerous. 😉